rollingcontact

Rolling contact is a contact condition in which two solid bodies touch and move relative to one another primarily through rolling motion rather than sliding. It is common in rolling elements such as ball bearings and roller bearings, gears, wheels, and cam followers. In ideal rolling, contact points have no relative tangential velocity, but real interfaces exhibit some micro-slip and friction, leading to wear and energy loss.

In contact mechanics, the interaction of elastic bodies under load is described by Hertz theory. For rolling contact, the contact patch has a finite size and a nonuniform pressure distribution. For spherical or cylindrical contacts, the load, geometry, and effective elastic modulus determine the contact radius and peak pressure. The subsurface stress field governs fatigue life and wear, influencing component reliability.

Rolling contact fatigue and lubrication are central to practical design. Repeated loading can cause rolling contact fatigue in bearing races and gear teeth, producing subsurface cracks. Lubrication reduces wear and friction; regimes range from boundary and mixed to hydrodynamic and elastohydrodynamic lubrication. Elastohydrodynamic lubrication is particularly relevant at high pressures in metal contacts, where a fluid film partially supports the load and alters the stress and wear patterns.

Applications and modelling: Engineers analyze rolling contact with analytical methods based on Hertz theory and with numerical tools such as finite element analysis. Material properties, surface finish, lubrication, and load distribution all influence life, performance, and efficiency. Rolling contact can also be compared with sliding contact, and the study of it is central to tribology and mechanical design.